The continual search for additional frequency bandwidth and efficiency from antennas in wireless systems points to the need for new approaches. Increasing frequency bandwidth of internal antennas for media applications in cell phones is a prime example. More specifically, FM radio and DVB-H TV reception are requirements in a large number of mobile phones. Antenna performance is a key parameter for good reception quality. Mobile handsets are very small compared to wavelengths at FM and DVB-H frequencies; accordingly the antennas used for these applications on handsets will be electrically small. These electrically small antennas will be narrow band and require low loss matching techniques to preserve efficiency. Multiple electrically small antennas embedded in a small wireless device will tend to couple, thereby degrading performance. The reduced volume allowed for an internal antenna coupled with the strict requirement that the internal FM and DVB-H antennas must not interfere with the main antenna or other ancillary antennas in the handset makes the task of antenna matching across the wide range of frequencies quite difficult.
Current market-available antenna designs and prior art antennas are not suitable for overcoming the aforementioned problems. Commonly owned U.S. patent application Ser. No. 12/117,669, hereinafter referred to as '669 discloses antenna embodiments useful over certain FM frequencies, the entire disclosure of which is hereby incorporated by reference. Although useful in many applications, the '669 application does not disclose the use of an impedance transformer for matching the antenna with a transceiver.
Taking into consideration the requirements for the next generation of devices along with the deficits of current technologies, a solution is needed which achieves efficiency from an internal antenna required to cover the large FM frequency band. Antennas commonly known and available which generally cover the entire frequency range tend to display inadequate antenna radiation efficiency at a fixed volume. There is an immediate need for improved antenna systems for providing efficient operation over FM and DVB-H frequencies while further providing a component volume capable of integration within strict and often very small design requirements of modern portable devices. There is a need for such antenna systems that will further reduce or eliminate interference with other antennas or wireless components in the portable device.